Tribological performance of hardfaced and heat treated EN-47 steel used for tillage applications

Abstract

In the present work, two different hardfacings, namely SZ (Super-Zed alloy; C3.83Cr33.37) and ZK (Zedalloy-K; C0.65Cr4.5Mo8.18) were deposited on EN-47 ploughshare steel by manual metal arc welding process to enhance the abrasive wear resistance. In addition, the influence of heat-treatment of steel by two different methods, i.e., carburizing (C) and through-hardening (Q&T), on the abrasive wear behaviour has also been investigated. Abrasive wear studies were conducted on bare, hardfaced, and heat-treated steel in a laboratory by using a three-body dry sand rubber wheel test rig as per the ASTM G-65 standard. The bare steel suffered a high wear rate, which may be attributed to its soft ferritic-pearlitic microstructure. The abrasive wear rate of tested specimens was found to be 1.7651 × 10−3 g m−1, 0.7439 × 10−3 g m−1, 0.961 × 10−3 g m−1, 0.992 × 10−3 g m−1 and 1.21 × 10−3 g m−1 for bare, SZ, ZK, C and Q&T steel specimens respectively. The SZ hardfacing provided better abrasive wear protection than the other treatments due to high chromium and carbon concentration in the hardfacings electrodes, which presented a higher area fraction of primary M7C3 carbides in the matrix. The wear resistance indices (WRI) for SZ hardfacing, ZK hardfacing, carburized, and through-hardened steel specimens were found to be 2.37, 1.84, 1.78, and 1.46, respectively.